1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel and a manufacturing method thereof, and more particularly, to an LCD panel and a manufacturing method thereof capable of preventing a voltage of an upper glass substrate from affecting amorphous silicon thin-film transistors (a-Si TFTs) by directly covering a conducting layer on a shift register using a-Si TFTs.
2. Description of Prior Art
An LCD panel of a conventional LCD comprises a plurality of pixels. Each pixel comprises three pixel units representing the three primary colors of light—Red (R), Green (G), and Blue (B). A gate driver outputs a scan signal which activates each TFT of the pixel units in each row to be turned on in sequence. Meanwhile, a source driver outputs corresponding data signals to the pixel units in a straight row. The pixel units obtain their individually required voltage at full charge to display different gray levels. The gate driver outputs a scan signal row by row to turn on each TFT of the pixel units in each row. Then, the source driver charges/discharges the turned-on pixel units in each row. Based on this sequence, all of the pixel units on the LCD panel are charged. After all of the pixel units are completely charged, the pixel units in the first row start to be charged again.
In a current LCD design, a gate driver comprises a shift register is used to output a scan signal to the LCD panel for every fixed time interval. For a gate driver adopting the a-Si TFT process, however, the shift register can be directly placed on a glass substrate. But, after the LCD panel is illuminated, the LCD panel often shows abnormalities due to a shift in the I-V characteristics of the TFTs. One reason is that the voltage applied on the upper glass substrate may affect the TFTs of the shift register, bringing about the shift in the threshold voltage of the TFTs. Consequently, the TFTs cannot effectively work and the life span of the TFTs is affected as well. Besides, the shift in the I-V characteristics of the TFTs can easily cause a power chip on a printed circuit board (PCB) to malfunction due to an overabundant flow of electrical current, resulting in display abnormality.